Graham Dowling, the International Cricket Council match referee, issued a warning to the touring side over the incident, which overshadowed Michael Slater's career-best 189 not out at the Waca Ground.
Dowling took no further action following a meeting with the Sri Lankan team management after close of play. It was the first time a team had been officially blamed for ball-tampering during a Test match.
"The Sri Lankan captain, Arjuna Ranatunga, was notified that the condition of the ball had clearly been altered by a member or members of his team during the course of the 17th over," Dowling said. "Furthermore, the umpires advised they would take appropriate action if there was any further attempt to tamper with the ball.
"The International Cricket Council does not condone such practices and I have made this abundantly clear to the Sri Lankan team management, with whom I have met since close of play," Dowling concluded.
Neither Dowling nor the umpires were available after the brief statement and Ranatunga declined to comment.
Sri Lanka have not usually been linked with ball tampering in the past. Most recent allegations, always denied, have been made against Pakistan. Last month the umpires during a Pakistan tour match wrote to the Australian Cricket Board expressing concern about apparent ball tampering.
The Pakistani captain, Wasim Akram, denied the accusations and the Australian board refused to comment, saying that match reports were confidential.
Whatever damage was caused to the ball here yesterday did not stop Australia's run spree as the home side finished the day on 358 for two in their first innings, a lead of 107 runs with three days left. Slater was in aggressive mood, lofting the ball over the boundary ropes five times and hitting 13 fours in posting his seventh Test century.
Slater and his opening partner Mark Taylor had Sri Lanka on the back foot from the start, adding 228 for the first wicket at more than four runs per over. Taylor fell leg before to Aravinda de Silva four runs short of his century.
David Boon was out soon after for 13, caught off bat and pad by Chandika Hathurusinghe off Muttiah Muralitharan.